Herbicidal compositions and processes of controlling undesirable plant species in the presence of crops

ABSTRACT

Herbicidal compositions and methods of controlling undesirable plant growth in the presence of important economic crops, using 2-nitro-4-((trifluoromethyl)sulfonyl)phenol are disclosed.

United States Patent [1 1 Walworth et al.

[451 Apr, 9, 1974 HERBICIDAL COMPOSITIONS AND PROCESSES OF CONTROLLING UNDESIRABLE PLANT SPECIES IN THE PRESENCE OF CROPS Inventors: Bryant Leonidas Walworth,

Pennington; Albert William Lutz, Montgomery Twsp., County of Somerset, both of NJ.

American Cyanamid Company, Stamford, Conn.

Filed: Mar. 4, 1971 Appl. No.: 121,163

Assignee:

US. Cl. 71/103 Int. Cl A0ln 9/14 Field of Search 71/103 References Cited UNITED STATES PATENTS 7/1969 Popoff et a1. 71/103 FOREIGN PATENTS OR APPLICATIONS 1,128,217 9/1968 Great Britain 71/103 OTHER PUBLICATIONS Shein et al., Chem. Abst. Vol. 66 (1967) 94446n.

Primary E.\'aminerLewis Gotts Assistant Examiner-Catherine L. Mills Arlorney, Agent, or FirmH. G. Jackson 3 Claims, No Drawings HERBICIDAL COMPOSITIONS AND PROCESSES OF CONTROLLING UNDESIRABLE PLANT SPECIES IN THE PRESENCE OF CROPS or aesthetically important plants such as food crops and ornamental plants.

Furthermore, many compounds which possess herbicidal activity are so expensive to manufacture that their use with large acreages is prohibited. A further problem encountered with many herbicidal compounds is the need to employ them at such high rates of application in order to achieve the desired herbicidally effective results, that their use creates a serious polluting effect upon the environment.

Accordingly, it is an object of the present invention to provide methods and compositions useful therein for the control of undesirable plant growth in the presence of important economic crops. lt is a further object to provide a process for the postemergence control and selective preemergence control of monocot and dicot weeds in the presence of important economic crops such as, for example, corn, cotton, soybeans and sugar beets. These and other objects and advantages of the present invention are further described below.

In accordance with this invention, it has been discovered that the control of undesirable plant species is achieved in the presence of planted and growing crops by applying to the planted area to be protected from such undesirable plant growth a herbicidally effective amount of a compound having the following formula:

03C Fa This compound can be readily prepared by heating 2-nitro-.4-[(trifluoromethyl)sulfone]anisole with pyridine hydrochloride. The anisole compound is in turn readily prepared by reacting a solution of sodium methoxide with 3-nitro-4-bromo-phenyltrifluoromethyl sulfone. The latter compound is well known in the chemical literature.

Several alternative routes which are suitable for use in the preparation of the subject phenol and related compounds are described in anumber of publications including: Chemical Abstracts 53: 21765i (1959); Zhur. Obshchei. Khem. 36 (12) and J. Gen. Chem. U.S.S.R. 36: 2135 (1966).

British Pat. No. 1,128,217 to Shell International Research C0. also discloses the preparation of several psulfonyl-phenol herbicides, the most preferred of which, namely, the 2,6-dihalo-4-(methylsulfonyl)- phenols, are compared to the compound of the present invention in Example 4.

It is generally preferred to employ the phenol in combination with conventional adjuvants, such as wetting or spreading agents, stickers, penetrants and emulsifiers; or, conventional solid or liquid diluents. The phenol may advantageously be formulated as a dust, dust concentrate, wettable powder, emulsifiable concentrate or as a granular product and applied to the foliage of plants or to the soil in which the plants are to be grown, using conventional applicators or soil incorporation equipment.

For postemergence uses, the phenol is applied to the foliage of the undesired plants in a herbicidally effective amount. Applications at rates of from about 0.33 to about 10.0 pounds per acre are generally preferred for this purpose. For use as a preemergence herbicide, the phenol is generally applied to the soil containing the seeds of the undesirable plant species. Applications at rates of from about 0.75 to about 9.0 pounds per acre are generally preferred for this purpose with rates of from about 0.75 to about 3.0 pounds per acre being especially preferred.

Dusts can be prepared by grinding from about 1% to 15% by weight of 2-nitro-4-[(trifluoromethyl)sulfonyl]phenol with from about 99% to 85% by weight of finely'divided clay such as attapulgite, bentonite or kaolin, talc, diatomaceous earth, fullers earth or similar diluents normally employed for this type formulation. Dust concentrates are made up in similar fashion, but from about 15% to by weight of the phenol is used.

Wettable powders are prepared in the same manner as dust concentrates, but generally about 1% to 5% by weight of a wetting agent, such as the oleic acid ester of sodium isothionate (Igepon AP- 78) and 1% to 5% of a dispersant, such as the sodium salt of polymeric carboxylic acid (Tamol 731), is included in the formulation. In practice the wettable powder is usually dispersed in water and applied as a dilute suspension to the plants or soil where weed control is desired.

Emulsifiable concentrates can be prepared by dissolving, usually about 10% to 25% of the phenol in about 89% to 74% of an organic solvent such as methylisobutylketone, benzene, xylene, methylethylketone, cyclohexanone or the like and admixing therewith from about 1% to 5% of a nonionic-anionic emulsifier such as Mol 77L (by Wm. Cooper and Nephews). This is dispersed in water for application.

The granular formulations can be prepared by dissolving the phenol in an organic solvent such as mentioned above, and sprayed on a sorptive granular carrier such as ground corn cobs, finely divided attaclay, kaolinite, or the like, or it may be mixed with a binder or sticking agent and applied to a nonsorptivegranule.

The following examples further illustrate the present invention but are not to be taken as being limitative thereof. In each case, the parts are by weight unless otherwise indicated.

EXAMPLE 1 Preparation of 2-Nitro-4-[ (trifluoromethyl)sulfonyl- ]ani sole Br OCH;

OzC F3 5020 Fa mole) in 500 ml. absolute methanol. The solution is brought to reflux for 2.5 hours after which the solvent is evaporated in vacuo. The solid obtained is recrysta1- lized from 95% ethanol to yield 24.4 g. (71.2%) of 2- nitro-4-[(trifluoromethyDsulfonyl]aniso1e, m.p. 76-79c.

Analysis Calculated for C H F NO S: C, 33.69; H, 2.12; F, 19.99; N, 4.91; S, 11.24. Found: C, 33.34;l-1, 2.12; F, 2l.29; N, 4.25; S, 11.47.

EXAMPLE 2 Preparation of 2-Nitro-4-[(tritluoromethyl)sulfonelphenol through a spray nozzle operating at 40 psi. for a predetermined time. After spraying, the plants are placed on greenhouse benches and are cared for in the usual manner, commensurate with conventional greenhouse practices. Two weeks after teatment, the seedling plants are examined and rated according to the Herbitoxicity Index provided below. When these data are compared with data obtained for 2-nitro-4- [(trifluoromethyl)sulfonyllanisole applied in the same manner at pounds per acre, the uniqueness of the compound of the present invention is apparent. Data obtained are reported in Table 1 below.

No A Herbitoxlclty Index 9 100% reduction in stand \N 9-- 1 or 2 stunted plants remaining 8 85- 100% reduction in stand i 7 70 85% reduction in stand 2O 6 60- 70% reduction in stand Pyridine hydrochloride 47.9 0.042 mole is f; 232' 228;: $33233: $33333 heated at 190 for 15 minutes in an open flask. 2-Nltro- 3 30- 40% reduction in stand r 2 Q 30% reduction in stand 4 {(tn tluorome thynsulfone] amsole (22.5 g., 0.079 1 reduction in Stand mole) 18 added in portions and the mixture heated at 0 no apparent effect 190 for 30 minutes. After cooling to room tempera- S =s'ivele F m moderate in ury ture, the mixture 18 diluted with water and then ext ="ace to slightinjury tracted with ether. Removal of the ether yielded the f g k crude product which after recrystallization from 1:1 ;g xf, ethanol-water gives 15.5 g. (72.2%) of 2-mtro-4- a abnormal growth [(trifluoromethyl)sulfone]phenol, m.p. 60-62C. r

Analysis Calculated for C H F NO S: C, 31.00; H, 1.49; F, 21.02; N, 5.17; S, 11.82. Found: C, 31.56; H, 1.55; F, 22.92; N, 4.49; s, 12.04. Plant Abbreviations EXAMPLE 3 K0 =Kochia v LA =Lambsquarters Postemergence Herbicidal Activity of 2-Nitro-4- Mu =Musmd I(trifluoromethynsulfonelphenol Pl =Pigweed The postemergence herbicidal activity of 2-nitro-4- g; :gig' gg [(trifluoromethyl)sulfonelphenol is demonstrated by 40 GRF =Green foxtail the following tests, wherein a variety of monocotyleg Om donous and dicotyledonous plants, including weeds and COT =C nq crop plants, are treated with the test compound dis- SOY y d I th I t .58 =Sugar beets perse 111 an aqueous-acetone mixture. n e es s, To =Tomam seedling plants are grown in iffy flats for about two WH =wheat weeks. The test compound is dispersed in /50 by vol- :g zigj g ume acetone/water mixtures in sufficient quantity to BT =Birdsfoot trefoil A =A1falfa provide the equivalent of about 0.33, 1 3 or 9 pounds Cw =Chickweed per acre of active compound when applied to the plants TABLE I Perennial Tree? weeds Annual weeds Crops men Structure lb./a. BW C'I KO LA MU RI BA OR GRF W0 COR COT soY SB T0 WH ET A. ow

OH 9999999339 m99 39rJ9999tt995m99- 19r99990tt9-t3 tm @NO: 0.33 0 9 9- 9- 9 mg t t t t 3 t t l SOzCFa OCHa 10 0 0 0 o 0 o 0 0 EXAMPLE 4 Selective Preemergence Herbicidal Activity of 2-Nitro- 4-[ tri-fluoromethyl)sulfone phenol The selective preemergence herbicidal activity of 2- ing. Seeds of the broadleaf weeds (i.e., pigweed, lambsquarters, smartweed. ragweed and jimpson weed) and grasses (i.e., foxtail and crabgrass) are broadcast over the plot and disked into the soil to assure heavy weed 1 nitro-4-[(trifluoromethyl)sulfone1phenol 1s demon- 5 ig i i 5 a strated in the following tests. These tests also show the en p an e soy 5mg "1" co on an sugar beets in rows approximately inches apart. vast superiority of this phenol over related methylsul- When plantings are complete, the plots are sprayed fonyl phenols such as 2,6-d1-1odo-4-(methylsulphonyl)- with an aqueous solution of the test compound using phenol and 2,6-dlbromo-4-(methylsulphonyl)phenol v disclosedin British Pat No 1 128 217 totshelumemyb 10 the sprayer to deliver the solutions essentially unitional Research C0 formly over the test plots. Untreated plots which have been similarly planted are employed as controls. At in- In the tests, seeds of a variety of monocotyledonous and dicotyledonous weeds and crop plants are sepatervals of four Weeks and SIX weeks afterfllammg. rately mixed with p g Soil and planted on p of p plots are examined and rated as to herbicidal activity roximatel one inch of ottin Soil in Se arate int according to the index set forth below. At both reads Aft lanti th p g S ta ed 3 th p ings, control plots adjacent to test plots are heavily inl e p e i p t e Sefested with all species of the broadleaf weeds and ec e liqueousface one u ammg comgrasses employed in the tests. Data obtained are repound in sufficient quantity to provide the equivalent ported in Table I" b d ow oizrbgutelgll1.2223225225 55 ls grz g g f l f g From the data it can be seen that 2-nitro-4- reenh use be riches and cared an in accord mce with [(trifluoromethynsulfonyllphenql applied at about 4 g d T k f pounds per acre, gave excellent (i.e., 70% to 80%) contgkll'eetnhpuze proce :ez. a lctiree \gee s a ter "@1 trol of broadleaf weeds with essentially no crop injury.

e es s re ermm e n eac cup 18 examine an rated according to Herbitoxicity index set forth in the 1 H b't "t Id F ldR't' previous example. The tabulated results of these tests er 1 y ex 1 "8 establish the herbicidal proficiency of the test compounds and are reported in Table [1 below. 0 9 Effect TABLE II Treaz- Annual weeds Crops Structure iii af KO LA MU PI BA CR GRF wo COR COT SOY SB TO WH Applicants compound:

OH 1.5 9 7 9 9 ta 7a 5a 0 0 0 0 0 l 1.0 9 5g 8g 7 ts. tg 5a 0 0 0 0 3 0 1.0 8 mg 9 9- ta 0 0 0 0 0 0 3 N z I SOzCFa Shell Patent Br. 1,128,217:

OH 20 o o o s o o 0 to o 0 0 0 I 1.0 0 o o o o o o o o o o 0 SOzCHa OH 2.0 o o 0 0 0 ,0 o 9-c n 0 tcg ta I 1.0 0 0 0 0 0, 0 0 s o o u ta Br Br I SOzCHa EXAMPLE '5 1 10% Selective Preemergence Herbicidal Activity of 2-Nitro- 2 20% H trifluoromerhyl su1f me1pheml :rgzzrzzias'azz'$5.22? Selective preemergence herbicidal activity of 2-nitro- 60 reduction in fresh weight of 4-[(trifluoromethyl)sulfonyl]phenol is demonstrated in 4 40% i f g fg P the following'tests wherein test compound is dissolved 5 I nluryi e 8 mm in 50/50 acetone/water solutions and applied in dilute A Value of 3 or less is accepw aqueous solution to seeded plots with a standard spray- 6 ble for p Selectivitying apparatus operated so as to deliver 57 gal/acre of 7 test solution which provides the equivalent of 2.0 or 4.0 lbs. of active ingredient/acre of seeded plot. The soil is 8 prepared in the normal manner by plowing and harrow- 9 10 Complete H Kill X Crop Not N0;

Injured Significant Injury K Crop I Killed 2. A method according to claim 1 for the selective AGW 233" I0 preemergence control of undesirable plants comprising Weeds applying to soils utilized for the growing of agronomic ABW Annual crops and containing seeds of undesirable plants be- Broadleaf tween about 0.75 and 9.0 pounds per acre of 2-nitro-4- weeds [(trifluorometh l)sulfon l] henol.

} 5 g y Y P TABLE lll interval/Weeks Rate lbs/A Sugar Beets Cotton Com Sorghum Soybeans AGW ABW 4 2 0 0 0 2 0 o s 4 4 0 o 0 0 5 3 s 6 2 4 3 0 6 6 4 0 0 l 0 7 We claim: 3. A method according to claim 2 wherein said phe- 1- A ho for the p m g control of unden01 is applied to said soil at from about 0.75 to 3.0 sirable plant species in the presence of planted crops pounds per acre comprising contacting the undesirable seeds thereof with a herbicidally effective amount of a compound of the formula: r 4 .l 

2. A method according to claim 1 for the selective preemergence control of undesirable plants comprising applying to soils utilized for the growing of agronomic crops and containing seeds of undesirable plants between about 0.75 and 9.0 pounds per acre of 2-nitro-4-((trifluoromethyl)sulfonyl)phenol.
 3. A method according to claim 2 wherein said phenol is applied to said soil at from about 0.75 to 3.0 pounds per acre. 